Endostatin inhibits the extension of F-actin–positive pseudopods in single endothelial cells. (A) Percentage of single cells extending pseudopods in endostatin-treated and control mice. (B) Single endothelial cells are either of an F-actin–expressing, pseudopod-extending phenotype (arrowheads) or a round phenotype with a low or absent expression of F-actin (arrows). Inserts show higher magnification. Scalebars, 50 μm.